Diesel is far from dead for BMW, with the company announcing two new straight-six, compression ignition engines for the 7-series. The company says the new engines will enhance the efficiency of numerous models of the BMW 7 Series.
Though not ‘new’ engines in the strictest sense, rather developments of existing models, the units have been heavily revised to comply with Euro 6d emissions regulations, and also feature 48V mild hybrid systems based on a starter-generator system, which can add an extra 8kW/11ps to the engine’s output.
The power unit deployed in the company’s BMW 730d model sees an output increase of 15kW/21ps to 210kW/286ps, with maximum torque raised by 30Nm to 650Nm, which is available between 1,500rpm and 2,500rpm. BMW said this is achieved by further refinement of the twin-turbocharger setup, which now comprises a two-stage system with variable intake geometry. The common rail direct injection system has also been optimized and delivers fuel to the combustion chamber at a maximum pressure of 2,700 bar.
The power increase provides BMW’s luxury sedans with even better acceleration. For example, 0 to 100 km/h for both the BMW 730d and the BMW 730d xDrive has now improved by 0.2 seconds to 5.9 seconds and 5.6 seconds respectively. This increase is accompanied by a fuel saving of up to 0.6 l/100km.
Meanwhile, the new generation of engines under for the 740d model have had power increased by 15kW/20ps to 250kW/340ps (maximum torque has risen by 20Nm to 700Nm). The main difference between the new and old versions is that the turbocharging system features variable intake geometry for both the high- and low-pressure stages.
Both new power plants feature exhaust aftertreatment, comprising a diesel oxidation particulate filter and an SCR coating on the diesel particulate filter. For optimum reduction of nitrogen oxide emissions, BMW said, a second dosage unit has been integrated at the outlet of the SCR fitted close to the engine. This has been necessary for the engines to meet the Euro 6d emission standard.